The Tour des Collines du Perche (TCP) is a 8 stage loop in the regions of Centre Val de Loir and Normandie, it is indicated via an orange blazon (see photo above). Several websites give descriptions of the route, lodging possibilities, the possibility to buy the guide book and the GPX files. (one site indicated below)
Randonnée itinérante - Site de letourdescollinesduperche ! (jimdofree.com)
The TCP comprises of gently rolling hills, beautiful old forests with many lakes and streams and beautiful little villages with wonderful old abbayes, chateaux, and churches. The route is not technical so most of the paths are runnable (mix of country lanes, tractor routes and single track) if wet parts of the course can be VERY muddy. I ran the route via the Belème variante (most beautiful) running 2 "walking" stages per day to complete the route in approx 78 hours.